1. Technical Field
The following disclosure relates to: a keyboard device including a plurality of key units superposed on and secured to one another on a key frame and each including (i) a common mounting portion elongated in a right and left direction and (ii) a plurality of keys having rear ends connected to the common mounting portion; and the key unit.
2. Description of the Related Art
There has been known a keyboard device including a plurality of key units assembled to a key frame and each formed of resin in one piece. Each of the plurality of key units includes a plurality of keys extending in a front and rear direction and arranged next to each other in a right and left direction; a common mounting portion; a plurality of hinges each shaped like a flat plate and provided between the common mounting portion and rear ends of the respective keys in a state in which upper surfaces of the respective hinges are horizontal. Patent Document 1 (Japanese Patent Application Publication No. 2002-62876) and Patent Document 2 (Japanese Patent Application Publication No. 2005-92233) disclose keyboard devices each including: a first key unit including a plurality of white keys respectively corresponding to notes D, F, and A; a second key unit including a plurality of white keys respectively corresponding to notes C, E, and B; and a third key unit including a plurality of black keys respectively corresponding to notes C#, D#, F#, G#, and A#. The first through third key units are superposed on each other in this order at their respective common mounting portions and placed on and secured to a rear end portion of a key frame by male screws.
In each of the first through third key units, each hinge includes: a hinge thick portion which is elastically deformed by a small amount when a corresponding white or black key is depressed and released; and hinge thin portions which are elastically deformed by a large amount, when a corresponding white or black key is depressed and released, so as to allow pivotal movement of a front end portion of the key in an up and down direction. A front end of the hinge thick portion is integrally connected to a rear surface of the corresponding key, and front ends of the respective hinge thin portions are connected to a rear end of the hinge thick portion, and rear ends of the respective hinge thin portions are connected to a front surface of the common mounting portion. In particular, in the third key unit including the black keys and located at the uppermost position among the first through third key units, the width of each hinge thick portion in the right and left direction is greater than that of a rear end of the corresponding black key in the right and left direction. Furthermore, in the third key unit, the pair of hinge thin portions having the same width in the right and left direction are spaced apart from each other in, the right and left direction and extend rearward from rear surfaces of respective opposite end portions of the hinge thick portion in the right and left direction. For each key of the third key unit, a right outer end of the hinge thick portion and a right outer end of a right one of the pair of hinge thin portions are located at the same position in the right and left direction, and a left outer end of the hinge thick portion and a left outer end of a left one of the pair of hinge thin portions are located at the same position in the right and left direction. Furthermore, an extremely small clearance is formed between the hinge thick portions for adjacent two of the black keys.